I read that the same power adaptor I use when traveling from the States to Europe will not work in South America. What do I need? Where do I get?

In Argentina, we use 220 volts and the plugs are different, but easily available.

If you are going to Brazil you will need different attachments for different places. Buy a universal adapter, I bought one on LAN that I've been using everywhere ever since. It won't change voltage but most things seem to have dual voltage now--computers, cameras, phones.

I would recommend waiting until you are here to get the adaptor. There are shops everywhere so they are easy to get and you will be able to know better which sorts of plugs you will need.

I will tell you that no adapter works on heating elements- re:flat iron or dryer. Most hotels had great hair dryers, were told to forget using our adapters on heating elements which we did try and almost burned out our very good flat iron. Argentina's power source is different from US and Europes.
Hope that helps.